Field of the Invention
The present invention relates to an aircraft antenna cover, an aircraft member cover, an aircraft, and a rain erosion boot for an aircraft.
Description of the Related Art
An antenna of a radar system mounted in aircraft is protected from wind and rain, sunlight, or the like by a bowl-shaped cover (called a radome). For example, the radome is formed of an insulating member in which a porous member is sandwiched between thin sheet materials.
When the radome is charged by friction with raindrops, snow, sand or the like, and the electrification charge is accumulated to cause an electrostatic discharge, there may occur a problem that noise is mixed into radio waves transmitted and received by the radar system. To prevent the problem, a conductive coating is applied to a surface of a substrate of the radome formed of an insulating material. The conductive coating is grounded to a metal member of an airframe. By transferring and diffusing the electrification charge into the airframe via the conductive coating, the electrostatic discharge is prevented.
The conductive coating covers the surface of the substrate of the radome to inhibit erosion of the substrate by rain impact, sand and dust, or the like, and thereby also functions to maintain high power transmittance of the substrate.
In addition to the conductive coating described above, a rain erosion boot that covers the conductive coating and inhibits erosion of the substrate by moisture, sand and dust, or the like over a long period of time is used. The rain erosion boot is formed in a film shape from a resin material such as polyurethane (JP2013-536776A). The rain erosion boot is provided at a front end portion of the radome to which a large load is applied by impact of raindrops, sand, or the like.
The rain erosion boot described above has an electrically insulating property, and keeps at the place and accumulates P-Static (Precipitation Static) charge generated by friction with raindrops, snow, sand, or the like. When an electric field strength by the accumulated electrification charge exceeds a dielectric breakdown strength of the rain erosion boot, a corona discharge, or an arc discharge and a streamer discharge occur from the rain erosion boot toward the conductive coating. These discharge phenomena due to P-Static are white noise, and cause electromagnetic interference in a communicator or a navigation receiver in a 100 MHz-band. Also, if a pinhole is formed in the conductive coating or the substrate by the discharge, erosion is caused by rain impact, sand, or the like, thereby resulting in a decrease in the power transmittance of the substrate.
That is, while the rain erosion boot is provided in order to reliably protect the substrate of the radome from erosion, the object of providing the rain erosion boot cannot be achieved if the discharge occurs due to the charge electrified on the rain erosion boot.
The corona discharge, the arc discharge and the streamer discharge described above are referred to as a “P-Static” in the present specification.
An object of the present invention is to ensure a cover erosion prevention effect by a rain erosion boot that protects a cover for covering an antenna mounted in an aircraft by preventing occurrence of a P-Static charge caused by friction between the rain erosion boot and raindrops, snow, sand, or the like.
The present invention is not limited to the antenna, and another object thereof is to prevent erosion and abrasion of a cover for covering various members mounted in an aircraft while preventing occurrence of a P-Static charge caused by friction with raindrops, snow, sand, or the like.